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Determining the stage of breast cancer

In order to guide treatment and offer some insight into prognosis, breast cancer is staged into five different groups. This staging is done in a limited fashion before surgery taking into account the size of the tumor on the mammogram and any evidence of spread to other organs that are detected. It is done definitively after a surgical procedure that removes lymph nodes and allows a pathologist to examine them for signs of cancer. The staging system is somewhat complex, but here is a simplified version.

Stage 0 (called carcinoma in situ)

Lobular carcinoma in situ (LCIS) refers to abnormal cells lining a gland in the breast. This is a risk factor for the future development of cancer, but this is not felt to represent a cancer itself. Ductal carcinoma in situ (DCIS) refers to abnormal cells lining a duct. Women with DCIS have an increased risk of getting invasive breast cancer in that breast. Treatment options are similar to patients with Stage I breast cancers.

Stage I

This is early stage breast cancer where the tumor is less that 2 cm across and hasn't spread beyond the breast.

Stage II

In this early stage breast cancer, the tumor is either less than 2 cm across and has spread to the lymph nodes under the arm; or the tumor is between 2 and 5 cm (with or without spread to the lymph nodes under the arm); or the tumor is greater than 5 cm and hasn't spread outside the breast.

Stage III

This is locally advanced breast cancer where the tumor is greater than 5 cm across and has spread to the lymph nodes under the arm; or the cancer is extensive in the underarm lymph nodes; or the cancer has spread to lymph nodes near the breastbone or to other tissues near the breast.

Stage IV

This is metastatic breast cancer where the cancer has spread outside the breast to other organs in the body. Depending on the stage of your cancer, your doctor may want additional tests to see if you have metastatic disease. If you have a Stage III cancer, you will probably get a chest x-ray, CT scan and bone scan to look for metastases. Each patient is an individual and your doctors will decide what is necessary to adequately stage your cancer.